This chapter tackles solidification defects, a major concern in metal casting. Shrinkage, caused by both solidification and cooling, leads to issues like porosity and cracks. The chapter offers analytical solutions for shrinkage problems in various casting designs. Foundries strive for defect-free castings that meet precise dimensions. However, shrinkage during cooling is a constant challenge. Volume changes during solidification (liquid-to-solid) and further contraction within the solid metal contribute to shrinkage. These processes can compromise castings by causing porosity or cracks. To clarify, liquid shrinkage happens before solidification, solidification shrinkage occurs during the phase change, and cooling shrinkage occurs in the solid state. The chapter explores “risers” as reservoirs of liquid metal within the mould cavity, which is a solution to shrinkage. Risers feed molten metal to the casting, compensating for shrinkage and promoting a sound casting. Both risers and the gating systems are typically recyclable. By examining foundry technology and intrinsic solidification defects, this chapter equips readers with the knowledge to overcome these challenges and produce high-quality castings.